Multicellular organisms, including mammals, are made up of tissues, that is, organized aggregates of specialized groups of cells of similar form and function. When tissues become damaged, an ordered series of physiological events must take place in a timely fashion for successful tissue regeneration to occur. The first events, termed the inflammatory phase, include blood clotting as well as the arrival at the wound site of cells that remove bacteria, debris and damaged tissue. Later, circulating stem cells migrate to the wound site and differentiate into tissue-specific cell types. Finally, the differentiated cells begin to produce and deposit new extracellular matrix, a complex assemblage of proteins and carbohydrates that provides support and anchorage for cells.
Successful repair of defective or damaged tissue depends, in part, on providing conditions that allow for appropriate cellular regeneration and that minimize the likelihood of infection during the repair process.